Patent Document 1 discloses a vehicle body in which a fuel tank is disposed below a driver's seat and below a front floor panel. A summary of a front portion of the vehicle body disclosed in Patent Document 1 is described with reference to FIG. 56 hereof. FIG. 56 diagrammatically shows a planar structure of the front portion of the vehicle body disclosed in Patent Document 1.
A front portion of a vehicle body 200 disclosed in Patent Document 1 accommodates left and right front side frames 201, 201 positioned on opposite sides in the vehicle-width direction, left and right floor frames 202, 202 extending rearward from the rear ends of the left and right front side frames 201, 201, and left and right side sills 203, 203 positioned outside the left and right floor frames 202, 202 in the vehicle-width direction, as shown in FIG. 56.
A front floor panel 204 runs between the left and right side sills 203, 203. The front floor panel 204 is a flat plate extending rearward from a lower portion of a dashboard 205, supported by the left and right floor frames 202, 202, and has a tunnel portion 206 having an upwardly protruding shape. The tunnel portion 206 extends from the lower end of a vehicle-width direction center portion of the dashboard 205 to a rear portion of the front floor panel 204. The front ends of the left and right floor frames 202, 202 are connected to the front ends of the left and right side sills 203, 203 by left and right outriggers 207, 207. Front portions of the left and right floor frames 202, 202 are connected to each other by a front cross-member 208. The rear ends of the left and right floor frames 202, 202 are connected to each other by a rear cross-member 209, which runs between the left and right side sills 203, 203.
A fuel tank 210 is disposed in a narrow space Sp200 under the front floor panel 204, between the left and right floor frames 202, 202, and behind the front cross-member 208.
When an impact acts on the front surface of the vehicle or when what is called a head-on collision occurs, the impact from the front side is transmitted through the left and right front side frames 201, 201 to the left and right floor frames 202, 202. Part of the impact is transmitted from the left and right floor frames 202, 202 through the left and right outriggers 207, 207 to the left and right side sills 203, 203. That is, the impact is distributed to the left and right floor frames 202, 202 and the left and right side sills 203, 203.
The front impact acts in the direction from the front to the rear of the vehicle body 200. On the other hand, the left and right outriggers 207, 207 extend in the vehicle-width direction. The direction in which the front impact acts greatly differs from the direction in which the left and right outriggers 207, 207 extend, which means that only the left and right floor frames 202, 202 receive most of the impact, and consideration therefore needs to be given to ensuring sufficient strength and rigidity of the left and right floor frames 202, 202. It is, however, noted that simply reinforcing the left and right floor frames 202, 202 disadvantageously increases the weight of the vehicle body 200.